The Journal of Medical Microbiology, Vol 47, Issue 9 773-779, Copyright © 1998 by Society for General Microbiology
Differential efficacy of passive immunisation against infection by Lyme disease spirochaetes transmitted by partially fed vector ticks
C. M. Shih and L. P. Liu
Department of Parasitology and Tropical Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China.
The efficacy of passive immunisation against tick-transmitted Lyme disease
spirochaetal infection was determined in relation to the duration of
previous feeding of infected vector ticks. Thus, mice challenged with
spirochaete-infected unfed or partially fed nymphal ticks were passively
immunised with monoclonal and polyclonal antibodies against the Lyme
disease spirochaete (Borrelia burgdorferi) at various intervals after tick
attachment. Spirochaetal infection in challenged mice and engorged ticks
was verified by xenodiagnosis and indirect immunofluorescent antibody
assay, respectively. Although tick-transmitted spirochaetal infection could
be aborted by anti-OspA antibodies and hyperimmune antiserum, nearly all
immunised mice challenged with infected ticks that had previous 36-h
attachment became infected. More than 72% of the nymphal ticks used in this
challenge retained their B. burgdorferi infection after engorgement on mice
immunised with anti-spirochaete antibodies, and their subsequent
infectivity to mice remained effective. It is concluded that a higher
efficiency of transmission by partially fed infected nymphs and a lower
efficacy of passive immunisation against infection result from an effect of
previous feeding of infected ticks that activates antigenic change and
enables the spirochaetes to circumvent OspA-based humoral immunity.
